Does intra-oral scan improve the impression accuracy of full-arch implant-supported prostheses: A systematic review and meta-analysis.

OBJECTIVES: The present study aimed to systematically review the studies comparing the accuracy of intraoral scan (IOS) and conventional implant impressions (CI) in completely edentulous patients. MATERIALS AND METHODS: Electronic searches were performed in PubMed, Embase and Cochrane CENTRAL up to December 1, 2023. Clinical studies and in vitro studies reporting the accuracy of digital full arch impressions were included. The primary outcome is the 3-dimensional deviations between the study reference models. A risk of bias assessment was performed for clinical studies. A stratified meta-analysis and a single-armed meta-analysis were conducted. RESULTS: A total of 49 studies were included, with 8 clinical studies and 41 in vitro studies. For comparison between IOS and conventional impressions, studies were categorized into two groups based on the different measurement methods employed: RMS and CMM. In studies using RMS, the result favored the IOS in the unparalleled situation with the mean difference of -99.29 µm (95% CI: [-141.38, -57.19], I2 = 81%), while the result was opposite with the mean difference of 13.62 µm (95% CI: [10.97, 16.28], I2 = 26%) when implants were paralleled. For different brands of IOS, the accuracy ranged from 76.11 µm (95% CI: [42.36, 109.86]) to 158.63 µm (95% CI: [-14.68, 331.93]). CONCLUSIONS: Accuracy of intraoral scan is clinically acceptable in edentulous arches, especially for unparalleled implants. More clinical studies are needed to verify the present finding.

[Effects and pathophysiological significance of intestinal flora on the enteric neuro-endocrine-immune system].

Interactions among the nervous, the endocrine and the immune systems enable the gut to respond to the dietary products, pathogens and microbiota, which maintains the homeostasis of the body. However, dysbiosis may induce or aggravate the gastrointestinal (GI) and extra-GI diseases through changing the activities of enteric nervous system (ENS), enteroendocrine cells and enteric immune cells. Here we review recent advances in the understandings on how intestinal flora may impact the enteric neuro-endocrine-immune system in the gut, thereby contributing to the regulation of pathophysiological processes.